Fire Ant Treatment: Baits

• Introduction
• Management Options
• Organizing a Community-Wide Suppression Program
• Treatment Methods

• Natural and Biological Control
• Physical and Mechanical Methods
• Control Devices
• Home Remedies
• Organic Insecticides
• Chemical Control

• Baits
• Contact Insecticides for Individual Mounds
• Mound Drenches
• Granular Products
• Dusts
• Injectable Products
• Surface Applications

• Biology and Identification
• Medical Problems
• History of Control Efforts
• Fire Ant Insecticides
• Policy Statement
• Acknowledgments
• Print this Lesson

Pile of fire ant bait compared to size of quarter. Photo by Kathy Flanders

Most conventional bait formulations combine pesticide ingredients with soybean oil, which is absorbed onto processed corn grit. Soybean oil is an attractive food for ants that is important to the success of the bait. Because these baits are granular in texture, be careful not to confuse them with granular products that contain contact insecticides. Fire ant baits should have the word “BAIT” clearly listed on the label. Baits can be applied as spot treatments to individual mounds, in a bait station, or broadcast over large areas (for additional information, see Texas Cooperative Extension publication B-6099, “Broadcast Baits for Fire Ant Control,” at Texas Cooperative Extension Bookstore). To achieve satisfactory results:

• Use fresh bait, preferably from a just-opened container or one that has been tightly resealed and stored for no more than 2 years. Purchase only enough bait to make one treatment and do not store large quantities once the containers have been opened. Bait is collected by ants only when it is fresh. It is then carried back to the colony and shared with other members of the colony. Rancid or stale bait is ignored by foraging ants. To check the quality of your bait, place a little near an ant mound to see if ants are attracted to it as described below.

• Apply when worker ants are actively foraging. This can be determined by leaving a small pile (1 to 2 tablespoons) of bait in the area to be treated. If you see ants actively removing the bait 10 to 45 minutes later, you will know that the bait is attractive and that ants are foraging. You can also use tuna fish, pet food, hot dog slices or potato chips to see if ants are foraging. Foraging activity slows when soil temperature is lower than 65 to 70 degrees F or higher than 90 degrees F. In mid-summer, apply bait in late afternoon or early evening, because foraging ants are less active during the heat of the day. Applying bait in early evening also prevents its being degraded by sunlight. In the winter, ants may not be foraging or be attracted to bait products.

• Apply baits when the ground and grass are dry and no rain is expected.

• Do not mix bait with other materials such as fertilizer or seed unless directions are provided for such mixtures.

• Use appropriate application equipment and calibrate it properly. Differences in the oiliness of bait brands and production batches can cause variations in applicator output. Temperature and humidity also affect the rate at which bait flows through the applicator opening. The speed at which the applicator is moving is an important factor, particularly with factory-calibrated settings. Over-application provides little or no increase in control and adds greatly to the cost. Under-application may decrease effectiveness.

• Do not store bait products near gasoline, fertilizer, or odorous pesticides, and do not smoke during bait treatments as these odors may reduce the bait’s attractiveness to ants.

The availability of bait products is a problem, especially in areas recently invaded by the fire ant. If you can not find some of the products mentioned in this publication, speak with the store manager, visit your local co-op, or contact your county Extension agent to determine whether the product is available in your area. Some of the bait products listed here are sold only through specialty stores such as lawn and garden supply stores or pesticide wholesalers that sell professional products.

Hand-operated spreaders, such as the Scott’s® HandyGreen hand-held spreaders, are the least expensive applicators and are adequate for treating small areas. The operator can walk or ride on the back of a vehicle. Some push-type applicators, such as Spyker® Models 24 and 44, also may be suitable, but some modification (attaching a fire ant plate) is required to keep from applying too much material. Most rotary and drop-type fertilizer spreaders will not apply fire ant baits at the recommended rate.

Electric spreaders such as the Herd® Model GT-77A or similar applicators are best for treating large areas. These spreaders have vibrating agitators that prevent clogging. Swath width is determined by spreader fan speed and the weight of bait particles and is usually fixed. Applicators can be mounted on any vehicle that will maintain a low speed. An air-assisted modification of the Herd seeder is available; it has a directional chute that allows faster travel and applies bait from only one side of the vehicle. Do not use ground-driven or power takeoff-driven equipment, because it can rarely be set to apply such a low rate. Aerial application requires some modifications to the aircraft and application equipment. A description of these relatively simple modifications and calibration methods can be obtained from bait product manufacturers.

In addition to their use as a broadcast treatment, baits can be used as an individual mound treatment or dispensed in a bait station. Bait products containing hydramethylnon, abamectin, fipronil or spinosad often work faster when used to treat individual mounds than when broadcast. This is not the case with insect growth regulator (IGR) baits containing fenoxycarb, methoprene or pyriproxyfen.

Related slide presentation, A History of Fire Ant Bait Technology